"Bob" wrote in message
...
Hello,

Was just wondering about this.

It is pretty well accepted, apparently, that a new asphalt driveway for a
residence should be laid over about 4" to 6" of gravel.
Never over soil directly.

Why ?

The hot, liquid, asphalt I would pretty much think makes the gravel into
one, solid, "clump" underneath (the asphalt).
So, it's hard to see that any improved drainage results.

Increased "stability" perhaps ? If so, how ?

So what does the gravel add as a benefit over just laying the asphalt
on top of well compacted soil ?

Thanks,
Bob

The folk responding about asphalt are right, so I won't duplicate their
effort. However, you might also be recalling the old Macadam road technique
with the modern version. http://en.wikipedia.org/wiki/Macadam

In my home town, many of the streets were Macadam and they did very well.
Occasionally, the street department would employ a tractor with wheel disk
to turn up the streets, and then they'd be rolled smooth, with a thick layer
of asphalt then applied. The final touch was a new coating of pea gravel to
reduce tar pick-up by car tires. The streets held up beautifully and the
technique most likely would be considered, "Green," in today's world.

Micajah